Method and apparatus for splicing film



Nov. 1, 1966 o. R. NEMETH 3,282,759

METHOD AND APPARATUS FOR SPLIGING FILM Original Filed March 5, 1962INVENTOR. OTTO R. NEMETH ATTORNEYS United States Patent 3,282,759 METHODAND APPARATUS FOR SPLICING FILM Qtto R. Nemeth, 11907 San Vicente Blvd.,Los Angeles, Calif. Continuation of application Ser. No. 177,286, Mar.5, 1962. This application Feb. 14, 1966, Ser. No. 539,238 2 Claims. (Cl.156-157) This application is a continuation application of my co-pendingapplication Serial No. 177,286, filed March 5, 1962, and entitled Methodand Apparatus for Splicing Film, now abandoned.

This invention relates to a novel method and apparatus for splicingfilm, tape, or equivalent material.

Film or tape is conventionally spliced by cutting the two film ends tobe connected together in straight transverse directions generally atright angles to the longitudinal axis of the film. A small length offilm emulsion is then scraped from one of the ends and the other endthen positioned to overlap the one end. Suitable adhesive is applied tothe scraped or cleaned end and the overlapped portions pressed togetherand held in position until the adhesive has set.

Another system for splicing film constitutes cutting straight transverseedges on the two ends to be secured together and abutting the same withthe film held in coplanar relationship. A suitable splicing materialsuch as a small portion of tape or the like is then caused to overlapboth abutting ends to secure the same together.

In both of the foregoing film splicing operations, there results anincreased thickness of the film at the point of splice. As aconsequence, the film is somewhat less flexible because of the doublelayer involved. Therefore, when the film is caused to execute relativelyshort turns of small radius of curvature such as when formed into theconventional loops between a projector pull-down structure and sprocketwheel, it exhibits a discontinuity rather than a smooth curve. Thisdiscontinuous portion may weaken the splice and oftentimes will resultin breaking of the film immediately adjacent the overlapping portions.

A double thickness of film at a splice point may be avoided by forming abutt splice. However, when attempting to butt the straight transverseedges of two film ends to be spliced together, there is provided verylittle cross-sectional area for the adhesive or other holding materialto gain a proper hold on the film. Therefore, such direct butt spliceshave usually been unsuccessful.

With the foregoing in mind, it is a primary object of this invention toprovide a greatly improved method and apparatus for splicing film ortape in which the foregoing disadvantages are overcome.

More particularly, it is an object to provide an improved method andapparatus for splicing film in which double or greater thicknesses areavoided at the point of splice to the end that when a film is caused toexecute short radii of curvature turns, there is not any appreciablediscontinuity in the film itself so that no weak points can thus developwhich might result in breaking of the film.

Briefly, these and other objects and advantages of this invention areattained by cutting or otherwise forming the two film ends to be splicedtogether in a manner to deviate from the conventional straighttransverse end edge so that a greatly increased effectivecross-sectional holding area is provided. By this arrangement, the twoends may be pressed together in abutting relationship and yet asufficiently large holding area is available to insure a strong splice.

A preferred apparatus for carrying out the foregoing operation comprisessuitable means for forming a cut in the ends of the film which may takethe form of an in and out path such as a sawtooth. Suitable means arethen provided for positioning the two ends of the film in oppos- "iceing relationship and biasing or otherwise urging the same together. Inaddition, a feature of the apparatus resides in the provision of upperand lower platens for confining adhesive or other material placedbetween the opposing ends so that there is assurance that the entireexposed butt end areas are wetted with the adhesive and take part insecuring the ends together. Moreover, the upper and lower platensprevent the overall thickness of the film from being increased anyappreciable extent by the adhesive itself.

A better understanding of the method and apparatus will be had byreferring to the accompanying drawing, in which:

FIGURE 1 is an exploded schematic illustration of one type of apparatususeful in effecting a splice in accordance with the present invention;and

FIGURE 2 is a side elevational view illustrating certain components ofthe apparatus not shown in FIGURE 1.

Referring to FIGURE 1, there is illustrated the method and apparatus ofthe instant invention. As shown, there are provided film ends 17 and 18each provided with end cuts 19 and 20 which differ from a straighttransverse cut in that the path defined by the cut alternates inwardlyand outwardly of the film. In the particular embodiment illustrated inFIGURE 1, this path is in the shape of a sawtooth.

The type of cut as shown can be achieved by a cutting blade such asindicated in the exploded portion at 21. If this blade is brought downin the direction of the vertical arrow, it may sever the end of the film17 to cause a sawtooth pattern as shown. The same cutting knife 21 maythen be turned in its plane to face in the opposite direction and effectan identical cut in the film end 18.

Since the second cut in the film end 18 is effected by the same cuttingmechanism 21 after the same has been rotated when this latter cut ispositioned in opposing relationship to the cut end of film 17, the twogroups of sawteeth or cut portions will mate perfectly. In other words,if one film is turned over 180, the film ends define perfect mirrorimages.

The actual mechanism for lowering the cutting member 21 may take anysuitable form but is not illustrated to avoid obscuring the drawings.The blade 21 could be operated manually if desired. In addition, itshould be understood that a cutting member having sawteeth to providethe cuts 20 in the film end 18 may be provided on the straight edge rearportion of the blade 21 so that only a single motion is necessary toeffect simultaneous cutting and thus properly condition the butt ends ofthe film.

As shown in FIGURE 1, the film end 17 and film end 18 are positioned ona lower platen 22. This platen is of somewhat less width than the filmto leave a marginal longitudinal edge 22'. This edge 22' serves in partas a guide for a pair of sprocket supporting members 23 and 24supporting sprocket teeth 25 and 26, respectively. These sprocket teethare arranged to pass through suitable sprocket holes in the film ends 17and 18 as shown. A stationarily secured dove-tailed slide member 27 maybe provided as a guide over which the members 23 and 24 may slide. Asimple biasing means in the form of a spring 28 is shown connectedbetween the members 23 and 24- to urge the same towards each other.

With the foregoing arrangement, it will be evident that the film ends 17and 18 can slide over the lower platen 22 to move towards each other.

With particular reference to the cutting blade 21, the preferredembodiment of the invention provides seven and one-half sawteeth foreach abutting end of the film ends 17 and 18. The extreme pointed endsof the sawteeth are separated by a distance d and the length or depth ofthe sawteeth are as indicated by the letter L. With this arrangement,the effective exposed butt end area A of each of the film ends isincreased by at least a factor of 2 over that which results from astraight transverse cut.

In FIGURE 2, there is shown an upper platen 29 arranged to be lowered toa distance T from the lower platen 22. This distance correspondssubstantially to the thickness of the film itself and serves to confineadhesive material 30 disposed between the opposing surfaces.

In effecting a splice in accordance with the method and apparatus of theinvention, the film ends are first cut by the cutting mechanism 21illustrated in FIGURE 1. These ends are then held apart against the biasof the spring 28 and suitable adhesive material disposed therebetween.The upper platen 30 is then lowered as illustrated in FIGURE 2 toconfine the adhesive to the space between the opposing film ends. Theslide members 23' and 24 and thus the sprocket teeth 25 and 26 are thenreleased so that the same are urged together to in turn urge the filmends 17 and 18 together so that the various exposed butt end areas willmate. The two film ends are then held in their mated position until theadhesive 30 has dried.

Since the adhesive has been substantially confined by the upper andlower platens 29 and 22, there is no substantial increase in the overallthickness of the film at the point of splice. Further, since a greatlyincreased area has been provided to which the adhesive may adhere, thesplice is sufliciently strong so that the film can execute shortradiused turns without breaking and without exhibiting anydiscontinuities so that the problems encountered with prior art splicesare avoided.

While only one particular embodiment of the invention has been set forthand described, the entire method and apparatus of this invention are notto be thought of as limited to such embodiment. Thus, while film hasbeen illustrated, this term is herein defined to include tape orequivalent material. Also, it will be appreciated that the sawtoothconfiguration, although preferred, is only exemplary of the type ofsplice embodied in the present invention. It is desirable, however, thatall mating portions of the abutting film ends be angled with respect tothe longitudinal axis of the film in order to obtain maximum squeezingof the adhesive therebetween.

It is also essential that the longitudinal length of the teeth orequivalent tapered members be such as to create sufficient resistingleverage to the tendency towards discontinuity as the result of filmmovement about paths of small radius. Furthermore, as heretoforementioned, it is necessary that the total area of service or abuttingarea be sufficient to at least equal in strength the non-spliced filmWhat is claimed is:

1. A method of splicing two film ends together, comprising the steps of:changing the butt end of each of said film ends from a straighttransverse end to an end extending in straight lines alternatelyinwardly and outwardly a plurality of times to increase the total buttend area of each end by a factor greater than 2, said ends being mirrorimages of each other when one film end is turned over and is in opposingrelationship to the other film end; inserting adhesive between theincreased butt end areas of said two film ends; urging the increasedbutt end areas of said two film ends together into pressing engagementWithout overlapping of any portion of said butt end areas; confining theupper and lower surfaces of the two films adjacent to their ends whenpressing the ends together to limit the escape of said adhesive frombetween the ends; and holding said butt end areas in pressing engagementuntil said adhesive has set, the increased area of bonding by saidadhesive being such as to provide a strength for said splice at leastequal to the strength of an unspliced portion of the film.

2. A film splice apparatus comprising, in combination: means defining acutting edge for cutting one end of two films to be spliced together ina path alternately extending in straight lines inwardly and outwardly aplurality of times to increase the butt end area of said one film endover the area resulting from a straight right angle transverse cut by afactor greater than 2, rotation of said cutting edge 180" positioningthe same for cutting the other film end in a similar manner so that saidfilm ends are mirror images of each other when one film is turned over180; means for positioning said two film ends in opposing co-planarrelationship, said means including at least one movable slide memberhaving sprocket teeth for engaging the end portion of one of said filmends and another member having sprocket teeth for engaging the endportion of the other of said film ends; biasing means connected to saidone member for biasing said one member towards said another member tobring the butt end areas of said film ends into mating engagement forbonding by an adhesive without any overlapping of any portions of saidbutt end areas; and upper and lower platens separated by a distancecorresponding substantially to the thickness of said film and positionedabove and below said film ends respectively to confine adhesive materialsubstantially to the space between the butt ends of said two film ends,the bonding area of said butt ends being sufficient to provide strengthin the resulting splice at least equal to the strength of an unsplicedportion of the film.

No references cited.

EARL M. BERGERT, Primary Examiner.

D. I. DRUMMOND, Assistant Examiner.

1. A METHOD OF SPLICING TWO FILM ENDS TOGETHER, COMPRISING THE STEPS OF:CHANGING THE BUTT END OF EACH OF SAID FILM ENDS FROM A STRAIGHTTRANSVERSE END TO AN END EXTENDING IN STRAIGHT LINES ALTERNATELYINWARDLY AND OUTWARDLY A PLURALITY OF TIMES TO INCREASE THE TOTAL BUTTEND AREA OF EACH END BY A FACTOR GREATER THEN 2, SAID ENDS BEING MIRRORIMAGES OF EACH OTHER WHEN ONE FILM END IS TURNED OVER 180* AND IS INOPPOSING RELATIONSHIP TO THE OTHER FILM END; INSERTING ADHESIVE BETWEENTHE INCREASED BUTT END AREAS OF SAID TWO FILM ENDS; URGING THE INCREASEDBUTT END AREAS OF SAID TWO FILM ENDS TOGETHER INTO PRESS-